Process and apparatus for the production of compounds of oxygen and nitrogen.



F. HABER a A. KOENIGL PROCESS AND APPARATUS FOB. THE PRODUCTION 0F GOMYOUNDS 0F OXYGEN AND NITROGEN.

APPLICATION FILED JULY 15, 1908.

. wwwa/awo fthe/Production of Compounds of Oxygen King-of Prussia an ject mixtures of nitrogen and oxygen,` pref- U'Nrrnn sans FRITZ .HABER AND` ADOLF KOENIG, 0Fr

A' CORPORATION. Y

PROCESS AND AP'PARATUS FOR THE PBOIDUCTEON OF COMPOUNDS 0F DXYG-Ehl IND i i i NITROGEN.

To all whoml 'it may concern:

Be it-known that We, FRITZ HABER .and Anonr KoENIc, subj cts, respectively, of the il the Emperor of Austriad'lungary, residing at Karlsruhe, Germany,.have invented, neW and useful Impi'ovements in Processes and Apparatus for andf Nitrogen, of which the following `is a specification. l

Our invention relates to a process and apparatus for the productionof compounds of oxygen and nitrogen' from mixtures thereof such for instance as air by means of an electric are.

In carrying out the process ofour invention We subject the gasmixture to the action of an electric arc while at a pressure not exceeding that of half an atmosphere and in an.apparatus of such rshape that the inside thereof is practically lled With arc flame, While the apparatus is cooled either by the natural escape of heat or by additional means of eoollng. By this means the concentration of the nitric oxid in the gases leaving the apparatus is increased and it is easy to produce gases containing from nine and one-half to ten per cent.' nitric oxid when using air, and from thirteen` and one half toA fourteen per cent. when a mixture of equal quantities of oxygen and nitrogen is employbd.

Accounts are vgiven in the literature of experiments v'vhich have been made to suberably air, to the action of the electric dis charge at pressures other than that of the atmosphere, in particular Lord Rayleigh (Journal Ulm/m.. Soc., 1897, vol. 71, p. 181) carried out experiments at pressures both' above and below that of the atmosphere. At a total pressure equal to half an atmosphere he obtained somewhat less favorable yields than those obtained at ordinary pressure;l he remarks, however, that the results point to the yield being almost independentmof the pressure. This conclusion is as a matter of fact correct in so far as mere alteration of the pressure alone does not produce results substantially diii'erent from those obtained at ordinary pressure. V

'The process of vour present invention diters from the previously described processes speciaeauon of reitersratem.

. .application med July 15, 190s. serial No. 443,745.

in that Whereashitherto attempts have been made to maintain as high a temperature as possible in thearc and coolthe products oi the vreaction as quickly as possible, in the process of the prsent invention the arc is kept comparatively cool by withdrawing heat and an extremely high `temperature is avoided. The reduced ressure also assists this cooling since the lischarge, which at ordinary pressure possesses the shape oita thin rod, expands and approaches the Walls of the apparatus, which bein cooled 'help 'to remove heat from the arc. n this Way discharge flames can be produced which lpractically no longer possess the Well-known brown Zone in,r which the nitricy oxid is believed to decompose partially back again to nitrogen and oxygen. The wall of the tube,

or the like, containing the arc should be maintained so cool that the arc does not spring across to it and thereby disturb the dischar e. If the natural escape of heat is not su cient for this purpose, special cooling means must be provided and this is advisable even if the tube, or the like, be made of material'which at ordinary temperature is a non-conductor of electricity, since at sufficiently high temperatures such material assumes the properties of a conductor.

The arc is preferably formed between metallic electrodes, or electrolyte electrodes, under which term We include, for instance, electrodes of magnesium oxid, calcium oXid and strontium oxid, and is allowed to burn in a long cylindrical vessel of which the Walls can, if necessary, be cooled from the outside. The establishment of the discharge can easily be brought about even When the electrodes are at a considerable distance from one another, for instance by reatly reducing the pressure for the time eing. "When once the are is created the pressure can be allowed to rise again, whereupon the eleotrodes, unless specially cooled (which in some cases may be desirable) become red-hot and the passage of the current is very much facilitated. In this way a long are column,

which appears to be quite stationary, is pro-l duced, and When the diameter of the tube, or the like, and the pressure of the vas are suit ably chosen, the are practically fills the mbe, or the like. Electrolyte electrodes have renera-lly the advantage of producing less dust Patented @et 26, its@ tained when the arc was than metallic electrodes.- Themixtures of nitrogen'and oxygen are passed through they of quartz which was cooled with Water and .the air or mixture of oxygen and nitrogen entered and-left the tube at a pressure of 90 mm. mercury, and with the low Velocity Vof one-fifth meter per second; In order to prevent decomposition of the nitric oxid at the red-hot electrodes, the entry and exit tubes for the gases can be so placed that the layer of gases around the electrodes is not renewed. The sectional current density, t'. e. the strength of the current per unit area of the cross-section of the tube should preferably.

be as high as possible.

It is difficult to define sharply the boundaries within which the pressure can be varied. No advantage, however, is obtained by 'reducing the pressure considerably under-180 mln. mercury. With. regard to higher pressures, it must be remembered that the higher the pressure the greater will be the velocity of decomposition of the nitric oxid. Experiments which were carried out at a pressure of 200 mm. mercury showed, however, that the upper boundary at which the usual small concentrations are obtained had not been reached.

The drawing accompanying this specification will assist in illustrating the nature of our invention, but we do not limit our invention to the apparatus there shown.

The drawing represents in section a suitable apparatus for carryin out the process.

A and B are the two e ectrodes and the arc which springs from one to the other is inclosed by'and practically iills the tubeC. Air or other mixture of nitrogen and oxygen is applied to and'drawn away from the tube C throu h the tubesD and E, which are so arrange that the gases surrounding ,the electrodes Aand B are'practically not renewed. l

F is a wider tube surounding the tube C and provided with entry and exit openings G and H through which a supply of cooling Huid can be introduced and removed.

K K and L L are tubes leading to and from the bases of the electrodes A and B, and through these tubes a cooling inid can be passed and assists in preventing the electrodes.- from vbecoming toohot.

i Nowy what we claim is:

K" l. The process of producing compounds a pressure not of nitrogen and oxygen from mixtures 'of nitrogen and oxygen by subjecting the gas mixture tothe action of an electric arc while at a pressure not exceeding that of half an atmosphere, and while causing the are flame to practically iill the vessel containing it substantially as described.

2. The process of producing compounds of nitrogen and oxygen from mixtures of nitrogen and oxygen y subjecting the gas mixture to the action of an electric arc while at a. pressure not exceeding that of half an atmosphere, `and while causing the arc flame to practically lill the vessel containing it and cooling the vessel substantially as described.

3. The process ofproducing compounds of nitrogen and oxygen from mixtures of nitrogen and oxygen y subjecting the gas mixtlire to the action of an electric arc While at exceeding that of half'an atmosphere and While causing the are flame to practically fill the vessel containing it, and cooling the external wall4 of the vessel, and while causing the layer of gases around the electrodes to be practically not renewed, substantially as described. j

4. Apparatus for producing or nitrogen and oxygen Afrom' mixtures of nitrogen and oxygen drical vessel in comb' ation with electrodes situated in and parallel to the' axis of the said cylindrical vessel, entry and exit penings for the gases and means for maintaining the gases in the vessel under reduced pressure.

5. Apparatus for producing compounds of nitrogen and oxygen from mixtures of nitrogen and ox gen comprising a cylindrical vessel in combination with electrodes situated inand parallel to the axis of the said cylindrical vessel, entry and exit openings fory the gases and means for maintaining the gases in the vessel under4 reduced pressure and means for cooling the external walls of said vessel.

6. Apparatus for Vproducing compounds of nitrogen and oxygen gen and oxygen comprising a cylindrical vessel in combination with electrodes situated in and parallel to the axis of the saidcylindrical vessel, entr'y andV exit o enings for the gases arrange so that the llayer ofi/gases around `lthe electrodes is practically not renewed means for maintamlng the gases inl FRITZ HABER. ADOLF KOENIG.

Witnesses:

A. REUTLINGER, Jos. ILLEULE.

compounds comprising a cylinfrom-mixtures of nitro- 

